Flow-Field Analysis of a Typical Hydrogen-Fueled Dual-Mode Scramjet Combustor Wei Huang 1 ; Lin Ma 2 ; Mohamed Pourkashanian 3 ; Derek B. Ingham 4 ; Shi-bin Luo 5 ; Jun Liu 6 ; and Zhen-guo Wang 7 Abstract: As one of the most promising propulsive systems for future hypersonic vehicles, the hydrogen-fueled dual-mode scramjet com- bustor has drawn the attention of an ever increasing number of researchers. The two-dimensional coupled implicit NS equations, the standard k À ε turbulence model, and the finite-rate/eddy-dissipation reaction model have been applied to numerically simulate the flow field of the dual-mode scramjet combustor, including the conditions of engine ignition and cold flow. The effect of the injection pressure and temperature on mode transition, and the movement of the shock-wave train, has been discussed. At the same time, the influence of the injection modes, namely, the transverse and horizontal, on the flow field of the combustor has been investigated. The obtained results show that the mode transition can be carried out by increasing the injection pressure and decreasing the injection temperature simultaneously. However, when the injection pressure is too high, the shock-wave train is pushed out of the isolator toward the entrance, and this causes inlet unstart. It has been found that the effect of the injection temperature on mode transition is smaller than that of the injection pressure. It is not easy to achieve mode transition when the fuel is injected horizontally into the airflow, and the combustion efficiency is lower than when the fuel is injected trans- versely. DOI: 10.1061/(ASCE)AS.1943-5525.0000136. © 2012 American Society of Civil Engineers. CE Database subject headings: Aerospace engineering; Combustion; Vehicles; Hydrogen; Fuels. Author keywords: Aerospace propulsion system; Scramjet combustor; Mode transition; Shock wave train; Hypersonic vehicle. Introduction Hydrogen is generally a more energetic fuel than hydrocarbon fuels for a Mach number range of 4–10 (Zhao et al. 2009), and it allows particularly low polluting processes without the complex exhaust gas treatment necessary for today’ s fossil energy (Peschka 1987). In the mid - 1960s, NASA built and tested a hydrogen- fueled and -cooled scramjet engine that demonstrated the cycle efficiency of the scramjet, the structural integrity, engine system integration, and the first-generation design tools (Voland et al. 2006). It also showed that hydrogen fuel can be used as a type of cryogenic fuel to provide significant cooling to the combustor (AlGarni 1996; Amati et al. 2008; Cui et al. 2008; Tsujikawa and Northam 1996). At the same time, hydrogen spreads rapidly, vapor- izes, and dissipates, thus reducing the threat to passengers and crew on hypersonic vehicles for surviving a crash (Rainey and Veziroglu 1992). Further, at the same Mach number, the specific impulse of hydrogen-fueled hypersonic engines is much larger than that of hydrocarbon-fueled engines, (see Fig.1). As one of the most impor- tant fuels that can be used in future hypersonic vehicles, hydrogen has drawn the attention of many researchers, and NASA has used it as the fuel for the X-43A and X-43D hypersonic projects (Moses et al. 2004). Among the types of propulsive systems, the dual-mode scramjet combustor is one of the most promising systems for the Next Generation Launch Technology (NGLT) Program (Charles et al. 2002; Moses et al. 2004), and also the HyFly program is based on this technology. In general, a dual-mode scramjet combustor consists of a constant area isolator followed by a combustor with a diverging cross-sectional area (Micka and Driscoll 2009), and it combines scramjet and ramjet flow paths into an integrated engine to achieve high performance over a wide range of speeds and successively works in both subsonic and supersonic combustion modes. Further, it can be used for the initial acceleration phase 1 Lecturer, Science and Technology on Scramjet Laboratory, College of Aerospace and Materials Engineering, National Univ. of Defense Technol- ogy, Changsha, Hunan, 410073, People’ s Republic of China; formerly, Ph.D. Candidate, Center of Hypersonic Propulsion, College of Aerospace and Materials Engineering, National Univ. of Defense Technology; and Centre for Computational Fluid Dynamics, School of Process, Environ- mental and Materials Engineering, Univ. of Leeds, UK (corresponding author). E-mail: gladrain2001@yahoo.com.cn 2 Senior Lecturer, Centre for Computational Fluid Dynamics, School of Process, Environmental and Materials Engineering, Univ. of Leeds, LS2 9JT, UK. E-mail: L.Ma@leeds.ac.uk 3 Professor, Centre for Computational Fluid Dynamics, School of Process, Environmental and Materials Engineering, Univ. of Leeds, LS2 9JT, UK. E-mail: M.Pourkashanian@leeds.ac.uk 4 Professor, Centre for Computational Fluid Dynamics, School of Process, Environmental and Materials Engineering, Univ. of Leeds, LS2 9JT, UK. E-mail: D.B.Ingham@leeds.ac.uk 5 Professor, Science and Technology on Scramjet Laboratory, College of Aerospace and Materials Engineering, National Univ. of Defense Technol- ogy, Changsha, Hunan, 410073, People’ s Republic of China; formerly, As- sociate Professor, Center of Hypersonic Propulsion, College of Aerospace and Materials Engineering, National Univ. of Defense Technology. E-mail: luoshibin@sina.com 6 Professor, Center of Hypersonic Propulsion, College of Aerospace and Materials Engineering, National Univ. of Defense Technology, Changsha, Hunan, 410073, People’ s Republic of China. E-mail: jr_junliu@sina.com 7 Professor, Science and Technology on Scramjet Laboratory, College of Aerospace and Materials Engineering, National Univ. of Defense Technol- ogy, Changsha, Hunan, 410073, People’ s Republic of China; formerly, As- sociate Professor, Center of Hypersonic Propulsion, College of Aerospace and Materials Engineering, National Univ. of Defense Technology. E-mail: zgwang_1960@yahoo.com.cn Note. This manuscript was submitted on June 15, 2010; approved on May 26, 2011; published online on May 28, 2011. Discussion period open until December 1, 2012; separate discussions must be submitted for indivi- dual papers. This paper is part of the Journal of Aerospace Engineering, Vol. 25, No. 3, July 1, 2012. ©ASCE, ISSN 0893-1321/2012/3-336–346/ $25.00. 336 / JOURNAL OF AEROSPACE ENGINEERING © ASCE / JULY 2012 J. Aerosp. Eng. 2012.25:336-346. Downloaded from ascelibrary.org by University Of Surrey on 08/31/12. For personal use only. No other uses without permission. Copyright (c) 2012. American Society of Civil Engineers. All rights reserved.